近50a阿勒泰地区大风的环流分型及预报

The Circulation Patterns and Forecast of Strong Wind in Recent 50 Years in Altay

利用1961～2010年阿勒泰地区7个观测站地面大风观测资料，统计分析了阿勒泰地区大风日数的时空分布规律及变化特征，结合2007～2012年35个大风个例的历史天气图、ECMWF和T213数值预报产品，进一步分析了大风天气环流特征，总结归纳出不同天气形势下大风预报指标和预报方法，并进行检验。结果表明：阿勒泰地区年大风日数为30 d，春季最多，冬季最少；各县市大风日数年际变化差异较大，均呈明显减少趋势，就全区而言，其气候倾向率为-8．5 d/10 a；受地形显著影响，西北部为大风多发区，东部最少。根据环流形势特征，该区大风主要分为冷锋型、动量下传型、回流型、中小尺度型4种类型。根据归纳的大风预报指标及预报方法，得出该地区2011～2012年大风预报准确率为77％，效果较好，在预报业务中具有重要的参考价值。

Based on strong wind days data at 7 weather stations of Altay area from 1961 to 2010,the temporal and spatial distributions of strong wind days and the circulation characteristics of 4 types strong wind processes were analyzed,firstly.Then,the forecast index and method were summarized on basis of 35 strong wind examples,such as historical weather maps,the ECMWF and T213 numerical forecasting product from 2007 to 2012.The results show that days of annual average strong wind in Altai area was 30 d.In four sea-sons,strong wind was most in spring,and least in winter.The annual changes of strong wind days at 7 weather stations were signifi-cantly different,but had obviously decrease trend in recent 50 years.In the whole area of Altay,the climate inclination rate of strong wind days was -8.5 d/10 a.The strong wind mostly occurred in northwestern Altay affected remarkably by the terrain,while the east was least.According to the circulation characteristics,the strong winds were divided into 4 types：the downward transmission of mo-mentum type,cold front type,reflux column type and the meso-scale and micro-scale type.The forecast effect was tested based on the forecast index and method,the accuracy rate from 201 1 to 2012 was 77%,which indicated that the forecast index and method had important reference in forecast service.